disconnecting session (black screen) often using gui and other tools on =22.04

Hello,
From a freshly installed jellyfish on an old laptop (testing machine).
Firstly, a lot of basics tools seemed missing, "users and groups :-O", "synaptic",.... not present

I experience trouble using several tools or basics actions :
As soon I try to use the search on synaptic, on cliking on an icon to launch a related GUI app (ie a .doc file to launch office, problem not occur if i first open libreoffice then from menu "Open..."), on webrowser (falkon, firefox,.. using right-click on a link, opening gmail.com, keytradebank.be, https://context.reverso.net/traduction....), launching notepad++, changing screen display, using gdebi (big crash)...
--> will exit / disconnect session (black screen for 20 sec. then send to the welcome session screen...)

I added gnome-session and gnome-shell-extension...an then if I start with gnome classique (wayland or X11) everything works ok... but it is not MATE anymore !!